Dermatology - Food Hypersensitivity Flashcards
Define adverse reaction to food.
an abnormal clinical response attributed to an ingested food or food product
Define food hypersensitivity.
an adverse reaction with a proven immunologic basis
Define food intolerance.
an adverse reaction to food that does not have a proven immunologic basis
Define idiosyncrasy to food.
a qualitatively abnormal response to a food or food additive that resembles a hypersensitivity
Define pharmacologic reactions to foods.
an adverse reaction as a result of a naturally derived or added chemical that produces a drug-like pharmacologic effect
Define metabolic reactions to food.
an adverse reaction due ot an effect of a substance upon the metabolism of the host, or as a result of defective metabolism of a nutrient by the host
Define food poisoning.
an adverse reaction to a food caused by a direct effect of a toxin
What types of hypersensitivity reactions are associated with food allergies?
Type I, and possible types III and IV
When dealing with food allergies, what must we remind clients?
that pets have reactions to ingredients in pet foods, not specific brands
What are the most common dog food allergens?
beef, dairy products, poultry products, wheat, corn, and many others
What are the most common cat food allergens?
beef, dairy products, fish, poultry products, and others
What patients typically get food allergies?
Dogs and cats, often after years on the same diet
What is specific about pruritus caused by canine food allergies?
It can develop at any age, it is non-seasonal, and is considered poorly responsive to glucocorticoids
What clinical signs are associated with food allergies in cats?
they may show pruritus, any sign of feline ‘reaction patterns’, ulcerative lesions, or self-inflicted wounds
What non-specific (to species) signs are associated with food allergies?
GI upset signs (in less than 25% of cases) and recurring pyoderma
What are some ways to diagnose food allergies?
history, elimination diets, and allergy testing (but not recommended)
What are some options for feeding trials?
novel protein diets or feeding hypoallergenic diets
How do novel protein diets work?
animals are fed diets that contain proteins to which they have not been previously exposed to
Homemade diets are preferred for novel protein diets, what are the preferred foods?
lamb and rice, fish and rice (or potato), tofu and rice (or potato), pinto beans and rice
What about hypoallergenic diets makes them good for food allergies?
the proteins are hydrolyzed to reduce the size of the protein to less than 18,000 daltons to reduce antigenicity
How long should food trials last?
minimum of 5 weeks, preferably 8-12 weeks in dogs
minimum of 6 weeks, preferably 8 weeks in cats
What happens if a pet is fed something, even a table scrap, during a food trial?
the trial must start over at day one, pets can not be fed anything flavored
True or false: A valid assessment is not made by changing brands of dog or cat food
TRUE
What are the recommended therapies for food allergies?
avoidance, corticosteroids (little benefit), or adding specific causative substances
What are the methods of avoidance in food allergy cases?
using homemade diets that are nutritionally complete and balance or using commercial hypoallergenic diets
Why would you want to add specific causative substances to a pets food?
To identify the offending substances, then find a commercial premium food that does not have it
What is the method of adding causative substances?
You add a new ingredient every 10 days and observe the patient for recurrence of lesions or pruritus
